Aims To investigate the yield of screening for atrial fibrillation (AF) in a cohort of 65-year-old individuals from the general population with additional risk factors for stroke. Methods and results We invited participants with additional risk factors for stroke (CHA2DS2-VASc score ≥2 for men or ≥ 3 for women) without previously known AF from a population-based study in Norway to participate in a 2-week screening for AF. Screening was performed by one-lead ‘thumb electrocardiography (ECG)’ recordings of 30 s twice daily or when the participants experienced symptoms. In total, 1742 (47.0%) participants of the Akershus Cardiac Examination (ACE) 1950 study had at least one additional risk factor for stroke. Of these, 123 cases reported a history of AF and 101 (5.8%) cases were ECG validated. Eight [0.5%, 95% confidence interval (CI) 0.2–0.9] new AF cases were diagnosed by 12-lead ECG at baseline, and 10 additional participants were diagnosed with AF before screening commenced. We invited all 1601 participants who met the inclusion criteria for screening, of which 1510 (94.3%) participants were included (44% women and 56% men). The screening revealed AF in 13 (0.9%, 95% CI 0.5–1.5) participants. The total prevalence of ECG-validated AF after screening among the 65-year-olds with risk factors for stroke was 7.6% (95% CI 6.4–8.9), in men 10.0% (95% CI 8.2–12.0), and in women 4.3% (95% CI 3.0–6.1) (P < 0.001). Conclusion In a group of 1510 well-characterized 65-year-olds with risk factors for stroke, 2-week intermittent ECG screening identified undiagnosed AF in 0.9%. The total prevalence of AF was 7.6%